Year	Percent
1970	70.72267
1971	71.57397
1974	75.31338
1975	78.72014
1976	78.63938
1994	98.68091
1996	93.61887
1997	92.18072
1998	100.08652
1999	98.21764
2000	98.49374
2001	98.08649
2002	102.03072
2003	99.92382
2004	98.56286
2005	96.68479
2006	99.1332
2007	101.8526
2008	105.0635
2009	104.98595
2010	104.80953
2011	104.42371
2012	103.23137
2013	100.88289
2014	101.81076
2015	101.48019